Expansion reamer



Mmh 21, 1933. w. H. EVANS' 1,902,062

EXPANSION REAMER Fil'ed Nv. 29, 1929 2 sheets-sheet 2 `Patented 2 1, 1933 UNITED sTATss PATENT or-Fics WILLIAM n. Evans, or caresse, Immers AssIeNon ro Evans FLExIiaLE amuse coaroiwrIoN, or omesso, rumors, .a couronner: or ILLINOIS murieron am Application med November 29, 1929. Serial No. 410,299.

My invention relates, in general, to reamers, and more in particular to reamers of the `type known as expansion reamers.

The'principal object of my present invention is the provision of an improved expansion rearner.

Another object is the provision of an expension reamer which will operate equally well and produce a smooth'finish on all types of work.

Another object is the provision of a reamer having a Along life.

Another object is the provision of a reamer which will cut a truly circular bore under all circumstances.

Other objects and features of the inven-` tion will be apparent from a consideration of the following detailed description, taken with the accompanying drawings, wherein- Fig. 1 is an elevational View, partly in section, of the entire reamer;

Fig. 2 is an enlarged transverse sectional view taken along the line 2-2 of Fig. 1;

Figs. 3 and Il are similar sectional views taken along the lines 3-3 and fl-4, respectively, of Fig. l

Fig. 5 is a sectional view similar to Fig. 2, but with the cutting segments having a different adjustment;

Fig.` 6 is a plan view showing the bottom surface of one of the segments;

Fig. 7 is a sectional view taken along the line 7-7 0f Fig. 2, and showing the mandrel and guides in elevation;

Fig. 8 is a similar view taken along the lineS-SofFi .5; f

Fig. 9 is a ragmentary elevational'y view showing the reamer fixed at right angles to Fi 1; and

ig. 10 is a sectional View taken along the line 10-10 of Fig. 7, and showing the sections at right angles to the sections of Fig. 7.

Concerning the general features of my reamer, I employ a center mandrel 11 with a pair of segments 12 and 13, guides 14 and 16, and confining collars 17 and 18, the details of construction of which will beset forth f hereinafter.

the. guides are also expanded for the same purpose. I support the segments in such a way that the cutting edges thereof are a1 provision of this character/lis made, it is practically impossible toi support the adjustable cutting members in such a way as to prevent this tendency to pull away from the mandrel and dig into the metal which is being operated on. The result of even a very 4slight pulling away of the cutting member is,

of course, to produc/e a very inferior bearing' `or roamed surface. yIn the present embodisegments bodily sid ways at the same time ment, I accomplish tgis result by shifting the that they are expan ed.

In order to employ the guides to best ad? Vantage, I also design the guides and their support so that they also will expand and simultaneously shift sideways, and so maintain the proper relationship. The cutting surfaces on the segments are arranged so that one cutting surface will move across the cutting path of the other Cutting surface and thus prevent grooving or scratching of the roamed surface. I tind that even if the cutting surfaces are slightly out of'line, a true cylindrical surface 'is produced without sc0r. ing the same, as if the segments had been sharpened true.y I consider that this is due to the fact that only two surfaces are cutting at onetime, but opposite each other, and with theguides between them, there is a natural tendency for the reamer to center itself under all circumstances. I find that if the reaming tool is mounted in a chuck, a perfect reamed surface is produced, even though the chuck may be out ofline so as to wabble perceptibly. The result of these features which I have explained is that substantially perfect -operation can be obtained on any type of metal.

Now, with further reference, first, to the tool as awhole, the confining collar 17 is of elongated construction and has one end bearingagainst a retaining spring 19, the opposite end of the spring bearing against a stop sleeve 21, secured to the mandrel by a pin' 22, with the end of the sleeve 23 formed to receive a wrench or other tool. The-collar 18 is engaged by an adjusting sleeve 24, which has internal threads for engaging a threaded portion 26 of the mandrel. The outer end of the sleeve 24 is shaped at 27 to receive a wrench and threads are provided in the portion 27 for receiving a lock-screw 28. These threads are of a left-hand type so that the loch-screw 28 may be forced against the end of the mandrel 29 to prevent the sleeve 2e from turning thereon.

In centering the nut 211, I provide two bear# ing surfaces therefomone on an extension 11a of the mandrel adjacent the conning collar 18, and t ie other against the smooth end of the mandrel 29, an unthreaded portion of the inside of the nut 2e bearing against this portion of the mandrel. In this way, I

- am able to make the threads between the mandrel and nut 2Llrelatively loose so that the nut can be turned freely, while at the same time being positively centered by engagement at the two places indicated. An exact centering of the confining collar 17 is obtained because this collar sets snugly throughout its length against the upper unthreaded portion of the mandrel.

Now, as to the specific support for the cutting segments, such support, as previously set out, is designed so that a compound adj usting movement is imparted thereto. Consider now Figs. 7 and 10. At opposite sides of the mandrel, oval segment supporting surfaces 31 and 32 are provided, corresponding with similar surfaces on the bottom of the segments. As Fig. 10 shows, these surfaces slant upwardly or away from the axis of the mandrel in a direction toward the collar 17. As Fig. 7 shows, theseV surfaces also slant at a side angleto the axis of the mandrel.A In other words, the supporting surfaces slant away from the axis in one plane, and across the axis in the opposite plane. The segments 12 and 13 have their reverse sides shaped to cooperate with the surfaces 31 and 32 to maintain the cutting edges parallel with the axis of the mandrel while receiving a compound adjustment movement.A As the nut 24'is tightened, for example, the collar 18 is forced against the beveled ends of the segments7 carrying the segments with it and driving them upwardly on the surfaces 3l and 32.. This movement is against the tension of the spring 19 so that, to adjust the reamer, it is simply necessary to operate the nut 24. If the reamer is to be made smaller, this expansion nut is simply released slightly and the spring will force the return of the segments. At the same time that the segments are being expanded, they move sideways as they advance along the supporting surfaces. Looking at Fig. 7 and comparing it with the surface on the reverse side of the segment, as shown in Fig. 6, it is obvious that the segment will shift bodily sideways while still maintaining a perfect alignment for cutting. The purpose and advantages of this feature will be explained more in detail herc- ,inaften 'Between the uides and segments there are wedge-shaped projections, or stop shoulders, 33 and 34g, formed integral wit the mandrel. These projections serve several useful purposes. Their principal advantage is that the segments are held against any possible rotation by bearing against them. In other words, they act as shoulders or stops for the segments. They determine the position of the segment supporting surfaces, andthe guide supporting grooves or slots, which slots are, therefore, slanted in a direction away from the sideways slant of the segment supporting surfaces. The result is that when the segments shift bodily sideways, the guides also have a similar side movement and this has an advantage in securing the best operation of the reamer.

In order better to explain the operation of the reamer, I show in Figs. 2 to 5, inclusive, a bushin 36, or similar member, in which a reammg operation might be performed. Fig 2 shows the position of the parts when the minimum or smallest diameter of the reamer is being used. Fig. 5 shows the parts where the maximum diameter of the reamer is being employed. I construct the reamer preferably so that, with the minimum diameter, the reamer is cutting in line with the dotted line A-A. This bisects the segments so that the cutting takes place at a point exactly between the two outside edges. With the reamer having its greatest' expansion, the cutting edges of the segments are along the line B-B,-that is, midway between the linevA--A and the trailing edge of the segments. The segments, therefore, cut at directly opposite places and bear on two points against the work 36. At'

through the axis of the mandrel and so pre,- vents any tendency of the segments to lift up. As a matter of fact, the tendency is just the reverse, and even without rigid su port at the ends of the segments by thev con collars 17 and 18, the segments Will be held tightly againstthe supporting surfaces, in-

cluding the members 33 and 34. Due to thisl construction and mode of operation, Iam able to design the Cutting edges on the segments so that one cuts across the path of the other at an angle, and so prevents the possibility of going over the saine path and causing a scoring or uneven cutting of the surface. l prefer the use of right-hand convolutions on one segment and left-hand convolutions on the other. l may, however, secure substantially this same result by simply making the eonvolutions of one segment run at a diderent angle than the convolutions on the other. I l By employing a new type of construction utilizing novel principles, l am enabled to use a very much harder cutting edge than has been possible in reainers of this type hereto.- fore, and so obtain extra long life and unusually good performance. l manufacture the segments from a mild grade of steel and then pack-hardenthem so that a glass hard cutting edge is obtained. Since there is no tendency for the cutting edges to dig into the surfaceswhich are being roamed, chipping of the cutting edges is avoided. This is also remedied in great part by the fact that the 35 very hard edge is backed by a` relatively softer material, which imparts to the tool, as a Whole, greater toughness than could be obtained with the usual tool steel. With the reamer of my invention, l can operate on all types of metal, including hard grades oi steel, case iron', copper,aluminum, and the like.

The reamer of my invention is employed in substantially the same Way as other reamers, the end 23 being engaged by a suitable tool, and the reamer rotated in a clockwise direction. Guides 37 and 38, made of spring steel, are provided for assisting in the cen-` tering of the reamer. These guides expand in such a Way Within an opening as to center the front or rear end of the tool, as the case maybe. rlhe segments themselves, with the guides, center this portion of the tool with no possibility of gettin out of mi As the drawings s ow, the ends oit the segments are beveled to lit under the collars 17 and 18. However, in order to allow for side movement oi the segments, l make the ends thereof slightly rounded as at 39 (Fig. 6). C3 rlhis perrmts the se ents to shiit readily and avoids the possity of a corner being wedged Vin under the collar, as might take place if these segments were cut square across the end.

Attention is called to the fact that the tening sion of the spring 19 is not adjustable, which is a feature di erin from other reamers which emplo a spring of this character. This means t at through the entire adjustment of the reamer, it is simply necessary to adjust from one end, and whether the spring 19 is oering a small amount of tension or a large amount of tension, the segments will not expand when the reamer is being used'.

The arrangement for adjusting the reamer to size is very satisfactory and ecient. ssume that the member 21 is held in a check and the reamer is being turned and the operator Wishes to enlarge the diameter of the remuer. While it is turning, he may enga e the lock nut 2S and allow the turning of t e reamer to loosen it a fraction of a turn, or a number oi turns, as desired. rlhen, by engaging the portion 27 of the nut 24:, the turnin of the reamer will tighten the nut 2d until the end ol the mandrel is again engaged by the' lock nut., rlhe expansion then will be equal to the amount the lock nut has previously been loosened.

WI le l amiable to secure the best results with my reamer by employing the combination of all of the novel features set out, the Construction may be modified considerably and good results obtained by using only some of these features. By using two segments.

'rather than any other'number, the reamer automatically lines up to produce a truly circular cut Without scoring, because it is cutting only on two points at any one time and these points are directly opposite each other. 'lhis feature can be used without the guides, hut l dnd the aides of considerable assistance when wor ring on certain types of metals. lHaring the convolutions reversed on the two segments, is also advantageous, be.- cause one cuts across the other and prevents scoringz en any considerable portion of the reamer is -in engagement with the Work, the reamer will line itself up because the outn lting surfaces engage from end to end of the segments. When the cutting edges, however, are just beginning to enter, the spring 37 is of great assistance in maintaining pertect ali ent,r without the use ci any other guiding means.

ile l have described the details of construction and operation of my reamer, to en- -able those skilled in the art to make and use the same, l ain not restricted to all of the features shown and described, but the 'invention is limited only by the scopeoi the appended claims.

at l claim as new and desire to protect by Letters Patent of the United States l. A reemer of the character described including e mandrel with a pair of supportin surfaces inclined to the axis of vthe mandre in a. radial place and at en angle to the axis in 'a chordal plane, a pair of segments with 130- iis iso

i eo

spiral cutting teeth, bottom surfaces corresponding to said supporting surfaces, and bevelled ends, retaining collars, one at each end of the segments adapted to lit over the 5 bevelled ends of the segments, a spring bearing against one collar, and an adyusting nut bearing against the other collar, the adjusting nut being so disposed with respect to the segments and their supporting surfaces that tightening thereof expands the segments and moves them bodily sidewise away from the direction of movement of the reamer when cutting.

2. A reamer of the character described including a mandrel having supporting surfaces inclined to the anis of the mandrel in a radial plane, and at an angle to the axis in a chordal plane, cutting segments having inner surfaces shaped to correspond to such supporting surfaces, and outer surfaces formed into a plurality of spaced cutting edges lying in a true cylinder at the smallest diameter, means Jfor supporting said segments against said surfaces, and means for advancing said segments along said surfaces to increase the diameter of the reamer and shift the segments laterally in direction opposite to the direction ci? rotation of 'the reamer when cutting, whereby the cutting portion oi the segments is shifted toward 'the trailing'edges thereof.

3. An expansion reamer comprising tivo semi-cylindrical segments provided with a plurality of spirally arranged cutting edges over substantially the entire periphery thereof, and a mandrel-slidahly supporting the segments, said mandrel having a pair of rounded surfaces each inclined outwardly and laterally and the segments having correspondingly shaped bottom surfaces so that s iiting the segments along the mandrel sur-l faces moves them radially dntwardly and laterally in a direction opposite to the normal direction of rotation of the reamer, whereby the cutting zone of the segments is transferred from the middle section thereof toward the trailing edge of the segments as the reamer is expanded.

4. A reamer of the character described inn cluding a mandrel having supportingsurfaces -inclined to the axis of the mandrel in a radial plane, and at an angle to the axis in the choral plane, cutting segments having inner surfaces shaped to correspond ,to such supporting surfaces, and outer surfaces formed into a plurality of spaced cutting edges lying in a true cylinder at the smallest diameter, means for supporting said segments against said surfaces, means for advancing said segments along said surfaces to increase the'diameter of the reamerand shift the segments laterally in a direction oppof' site to the direction of rotation of the reamer when cutting, whereby the cutting portion 86 of the segments is shifted toward the trailing i 'attaccati` edges thereof, and shoulders on the mandrel engaging and supporting the trailingedges of the segments.

5. A reamer of the character described including a mandrel having 1pportin surfaces inclined to the axis of the mandrel in a radial plane, and at an angle to the axis in the `chordal plane, cutting segments having inner surfaces shaped to correspond to such supporting surfaces, and outer surfaces *formed into a plurality of spaced cutting edges lying in a true cylinder at the smallest diameter, means for supporting said segments against said surfaces, means for advancing said segments along said surfaces to increase the diameter o the reamer and shit the segments laterall in a direction opposite to the direction o rotation of the reamer when cutting, whereby the cutting portion oi the segments is shifted toward the trailing edges thereof, shoulders on the mandrel en gaging and supporting the trailing edges of the segments, guide members, one Vtor each segment, lying between said shoulders and the leading edges ot the segments, and means for expanding the guide members as an incident to the expansion of the segments.

ln Witness whereof, E hereunto subscribe y name this 25th day of November, i929.

WiLLldlf/ll EVANS. 

